Rolling of thin gauge sheet metal



May 23, 1933- W. STRINGHAM 1,910,648

ROLLING OF THIN GAUGE SHEET METAL Filed July 14, 1930 OOOOO/f .l uUuuuUuuuUuQ-U A TTORNEYS Patented May 23, 1933 UNITED STATES PATENT OFFICE WILLIAM STRINGHAM, OF FRANKLIN, OHIO, ASSIGNOR TO THE AMERICAN ROLLING MILL COMPANY, OF MIDDLETOWN, OHIO, CORPORATION 0F OHIO ROLLING OF THIN GAUGE SHEET METAL Application led July 14, 1930. Serial No. 467,911.

My invention relates to processes of rolling metal to thin gauge, particularly iron and steel sheets, and its primary object 1s the attainment of better control in the rolling mill, by which I mean a more perfect coordination of mechanism, labor and manipulations to the end of producing a greater tonnage of thin gauge sheet metal at a lower cost. Thus an important object of my invention is the rolling of metal pieces to thin gauge sheets with fewer manipulations.

Still another object of my invention is the provision of a method of rolling a starting piece in the nat-ure of rough plate, to

thin gauge sheets with a minimum number of passes through the mill and without .any re-heating. In this way, I attain, and i't is one of my objects to attain, (using rough plate as a starting piece) a one-part system of rolling such starting pieces to thin gauge metal, as distinguished from the three and four-part systems which have hitherto been almost universally employed for such reductions. l

An ancillary object of my invention is the provision of a process of reduction which utilizes the rough plate now being iliade commercially upon continuous mills, and 1s available in replacement of sheet bars or other relatively less advanced starting pieces commonly used heretofore.

My invention is not limited to rough plate as a raw material however, as will' be apparent from the ensuing description, al-

thongli it furnishes an especially advantageous method of utilizing this relatively new raw material. I

These, and other objects of my invention which will be pointed out hereinafter, or

40 will be apparent to one skilled in the art upon reading these specications,.I accomplish by that certain series of manipulations forming the process which I shall now describe in av preferred embodiment, reference being had to the drawing which forms a part hereof.

In the drawing Figure 1 is a diagrammatic drawing of the apparatus required for the carrying on of my process,

'Figure 2 shows diagrammatically several steps of my process and Figure 3 is a diagram illustrative of the several stages of reduction effected by me in producing thin gauge metal from rough plate.

I shall describe my process as applying to iron or steel sheets of 26 gauge as exemplary. This gauge is equivalent toa thickness of 0.01875 inches. It will be understood, of course, that this gauge is not limiting upon my invention and that other relatively thin gauges may be made by me with equal facility. It will be understood, also as an original premise, that iii the rolling of sheet metal, it is not commercially convenient to roll a piece or pack of metal much thinner, if at all, than 0.1 of an inch inasmuch as the spring of the rolls is such that reduction beyond this point is not effected with desirable uniformity; consequently, for thin gauge metal, it is desirable, if not commercially necessary, toroll it in multiple, i. e., in packs of a plurality of separate sheets, at least in the finishing operation.

Thus in a standard prior process which I refer to as a four-part system, a pair of sheet bars are heated and roughed, are

matched and given matching passes, then reheated and rolled. They are then doubled, reheated and rerolled. Next they are redoubled, and the first doubled and sheared off. Finally they are reheated and finished.

In another system which I refer to as a three-part system, a lighter bar is chosen. The bars are heated and broken down on the roughing mill. The rough plate is matched in packs of three or more and relieated in the sheet furnace, run over with one or more passes and doubled, and the doubles are reheated and finished.

The old method of rolling iron or steel sheet from sheet bars without doubling, may be referred to as a two-part process. The bars lare heated and broken down on a roughing mill as a first step. The rolled sheets are then matched, reheated and rerolled as a second step. This process is, however, not available for the making of relatively thin gauge material, for the reason that in it the packs do not contain enough separate sheets to permit the extreme reductions necessary to the production say of 26 gauge metal or lighter.

One-part systems for 18 gauge metal or heavier, have been devised, but these obviously are inadequate to the end of my present invention.

My new process is essentially a one-part o1' single step system for producing lighter gauges. Broadly, it comprises doubling a pair of rough plates cold, heating the double pairs thus formed, taking out of the furnace two of the doubled pairs or packs, and giving each pack one or more passes singly before matching, then matching the packs and giving the matched packs one or more passes all Without reheating.

Referring to Figure l, l have shown as the necessary apparatus, a doubling mechanism indicating at l, a heating furnace 2 and a rolling mill 3 of the two-high type, all of these devices equipped with the necessary conveyors and the like. These devices are old in the art and do not need special description by me.

Referring to Figure 2, to make my process clear, it will be understood that l start with four rough plates. l take a pair of the rough plates 4, lmatch them and pass them through the doubling mechanism l, so as to form a doubled pack, four sheets in thickness. This pack li have indicated at 5. rliwo packs are formed. rlfhe doubling, particularly where the starting pieces used are rou h plates formed in a continuous mill, is pre erably done cold. rlhe continuous mill is usually located in a separate part of the plant, or may be located in a dierent plant inasmuch as continuously produced rough plate is now a commercially available article of commerce. The advantages of producing rough plate on the continuous mill as developed in recent years, do not need special description. ln the continuous mill, as is well known, slabs previously formed by rolling from ingots are continuously rolled in a train of tandem hot mills to form rough plate stock, which is then sheared apart into rough plates. The product of the continu ous mill forming rough plates is usually handled and shipped cold. l am not restricted, however, in my invention to the cold doubling of pairs of rough plates, nor am ll restricted to the 'use as starting pieces of continuously produced rough plates. When delivered hot and doubled, any residual heat remaining in the doubled packs, will, of course, cut down the necessary time for heat ing the packs in the furnace. Whether l employ cold rough plate produced continuously, in a continuous mill, or rough plate delivered cold or hot, heating will be necessary before any further reduction is effected upon the plate, and it is one of the essentials of my invention that l' pair and double the rough plate before this heating step. lf am enabled in my process, however, to use heavier rough late than otherwise.

In the first step o my process, l lay the foundation for one of its chief economies, in that I match and double rough plates before the reheating. So far as l am aware, it is only by this step that l am enabled to carry on the subsequent reduction of the metal to thin gauge in a one-part process, i. e., without reheating. 'lhere is in my process but one heating step. When referring to a rolling method as comprising one or more parts, I take each part as comprising a heating step and a rolling step.

The doubled pairs of rough plates 5 are placed in a heating furnace 2, and brought up to the required temperature. lt will be observed that the pieces heated comprise four thicknesses of rough plate, consequently, l attain in my heated pieces the maximum capacity for retaining heat, and this is an important factor in my process. lt would not be possible to take rough plate, heat it and roll it singly, afterward matching it, doubling it, or both, and rolling it to thin gauge metal without one or more intermediate reheatings.

As the next step in my process, ll withdraw from the furnace a pair of the heated doubles 5, and taking them to the rolling mill 3, ll. roll each of the doubles singly, giving it one or more passes and preferably rolling by the under and over method in which a pack is sent through the rolls while the catcher returns a previously rolled pack over the rolls.

The packs are passed through the rolls with the doubled edge foremost, and the type of rolling is that known as tight rolling.

Having sent the packs 5 through the rolls singly as described, l next match the packs, send them through the rolls together, with one or more passes, the doubled ends foremost, thus finishing the sheets to thin gauge, all without reheating.

'lo illustrate the manner of reduction, reference is now made to Figure 3, in which l have shown rough plates 4 as constituting the starting pieces. The rough plates, say, are of l5 gauge and .070 inches in thickness. lt will be understood that these and the remaining figures which I shall give, are exemplary, and that l may employ different gauges of rough plates and finish in different relatively thin-gauges, without departing from the spirit of my invention. When the rough plates 4 are matched and doubled, they form a pack 5, four rough plates in thickness. Assuming that the metal was in tight contact, such a pack would be say 27 inches long, including scrap and .280 inches in thickness. T he doubled packs 5 are next to form the pack 6, which is now eight sheets in thickness, 60 -to 72 inches long and sal v .18 to '.20 in thickness. The matched pac 6 is next rolled with one or more passes throughthe mill, whereby it is elongated, say to 96 inches. I have indicated the elongated pack by the numeral 7. It will have,

say a thickness of 0.15 inches, and the individual sheets will have a thickness of 0.01875 inches, corresponding to 26 gauge metal.

Instead of the two-high mill 3, which I have shown, I may, of course, use other types of mills. The four-high mill isl suitable for use in my process, alt ough I have so simplified the operation and cut down the number of manipulations that I canpractice my process and produce thin gauge sheet metal in one heat without finding it necessary to employ the extremely heavy reductions for which the four-high mill is especially adapted. Consequently, I prefer-to use the twohigh mill, by reason of its relatively smaller initial cost. The three-high mill as ordinarily used, is not suitablel for my process because on the reverse pass the packs would be entering the mill with the free edges first and this would obviously be undesirable. If a three-high mill were equipped with a turn table, or some other device suitable for reversing the packs so that they would enter the return pass, doubled end foremost, such a mill might be employed. So far as I know the operation of reversing the packs would offset the time saved in utilizing the back pass of the4 three-high mill; although I recognize that with a pack reversing mechanism, the three-highy mill might be employed in my process.

It will be obvious that modifications may be made in my rocess without departing from the spirit o my invention.

Where in the following claims I have used the words doubling or double I refer to a folding over of the piece or pack used, and the folded article produced thereby.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process for producing sheet metal from slabs, which comprises continuously rolling a slab to produce rough plates, matching and doubling rough plates, heating the matched and doubled plates and then reducing the plate to finished gauge without reheating.

2. That process of producing sheet metal from slabs, which comprises continuously hot rolling a slab to produce rough plate stock, shearing the rough plate stock into rough plates, matching and doubling rough plates cold, heating the matched and doubled rough plates and reducing them to finished gauge 1n amill without reheating.

3. A rocess of producing thin gauge sheet metal rom ingots which comprises rolling an in ot to form slabs, continuously hot rolling s abs to form rough plate stock, shearing the rough plate stock into rough plates, matching and doublin rough plates, heatin matched and doub ed rough plates and re ucing them to finished gauge without reheating.

4. A process of producing thin gauge sheet metal from ingots which comprises rolling an ingot toV form slabs, continuously hot rolling slabs to form rough plate stock, shearing the rough plate stock into rough plates, matching and doublin rough plates,

heating matched and double rough plates and reducing them to finished gauge wlthout reheating by steps which comprise first reducing a pair of matched doubles, then matching the mat-ched doubles and rolling them as a pack.

5. A process of producing thin gauge sheet metal from slabs, which comprises continuously rolling a slab to form rough plate stock, shearing said stock to produce rough plates, matching rough plates and doubling the same cold, heating the doubles thus formed to rolling temperatures and in a. hand mill rolling singly a pair of heated doubles, matching the heated doubles and rolling them together to finished thin` gauge, all without reheating.

6. A process of producing thin gauge metal sheets from slabs, which comprises hot rolling slabs in a train of continuous tandem hot mills to form rough plate stock, shearing the rough plate stock to form rough plates, matching the'rou-gh plates and doubling the .same cold, heating the doubles thus formed and giving them one or more `single passes through a rolling mill, matching the rolled doubles and rolling with one or more passes to finished gauge in the same mill, all without reheating, the rollin bein of the type known as tight rolling, t e pac s being sent through the rolls double end foremost in each ass.

v eight-thickness pack,'and rollin the eightthickness pack to substantially t e commer cial limit of reduction in single passes, all

without reheatin WI IAMSTRINGHAM. 

